CHEM 1031

Stoichiometric Ratio

Procedure

PUT GOGGLES AND APRONS ON.

Equipment Needed (per pair):

• (2) 400 mL beakers

• (2) 100 mL graduated cylinders

• (1) desk thermometer

• (1) stirring rod

• (1) calorimeter cup (obtain from sideshelf)

Procedure (Continued)

RECORD DATA IN INK, AND PUT NAME,PARTNER’S NAME, AND DATE ON FIRSTDATA SHEET.• Obtain 350 mL of the 0.50 M NaOCl and

0.50 M Na2SO3 solutions in separate 400 mL beakers. OPEN AND CLOSE CARBOY VALVES VERY CAREFULLY.

• “Guesstimate” 350 mL above the 325 mL mark.

Procedure (Continued)

• Put thermometer in one of the beakers and measure and record temperature, estimating to the nearest 0.1oC. This is the initial temperature (same for all seven runs).

• Set up ring stand, calorimeter cup, and thermometer thus:

Procedure (Continued)

FOR EACH RUN:

• Measure out prescribed volumes of NaOCl and Na2SO3 solutions using separate

100 mL graduated cylinders.

Procedure (Continued)

• Combine solutions in calorimeter cup and stir with glass stirring rod.

Procedure (Continued)

• Measure and record maximum temperature to the nearest 0.1oC.

• Pour wastes down drain.

Procedure (Continued)

• Rinse calorimeter cup with tap water and return to sideshelf when done.